Bearing arrangement for a spinning rotor of an open end spinning device

ABSTRACT

A bearing arrangement for a spinning rotor of an open end spinning device wherein the spinning rotor comprises a shaft, at one end of which there is mounted a turbine and at the other end of which there is mounted a drive whorl. Antifriction bearings are provided for supporting the rotor shaft and the exterior of such bearings is rigidly mounted in a sleeve surrounding the rotor shaft. The sleeve is connected with the walls of a bore in the rotor housing via an elastic member surrounding such sleeve. The sleeve is a thin-walled light and rigid metallic sleeve member and the elastic member comprises a ring of elastomeric material placed upon the end of the thin-walled light metal sleeve facing the turbine. The ring provides an airtight seal for the room or compartment between the sleeve and the bore in the housing at the side of the ring facing away from the turbine. Further there are provided means between the ring sealing the compartment and the drive whorl for permitting penetration of air into said compartment between the sleeve and walls of the bore in the rotor housing. Such air penetration means may be constituted by a second elastic outer support member provided for the sleeve at the other end at the drive side confronting the drive whorl and/or by one or a number of holes or bores provided at the rotor housing.

United States Patent [191 Mandl [4 1 Oct. 14, 1975 BEARING ARRANGEIVIENTFOR A SPINNING ROTOR OF AN OPEN END SPINNING DEVICE Gerhard Mandl,Winterthur,

Switzerland [73] Assignee: Rieter Machine Works Ltd.,

Winterthur, Switzerland [22] Filed: Apr. 8, 1974 [21] Appl. No.: 459,199

Related US. Application Data [63] Continuation-impart of Ser. No.383,722, July 30,

1973, abandoned.

[75] Inventor:

[52] US. Cl. 57/58.89; 57/130; 308/26 [51] Int. Cl. DOIH 1/12; DOll-l7/04 [58] Field of Search Primary Examiner lohn Petrakes Attorney,Agent, or FirmWemer W. Kleeman [57] ABSTRACT A bearing arrangement for aspinning rotor of an open end spinning device wherein the spinning rotorcomprises a shaft, at one end of which there is mounted a turbine and atthe other end of which there is mounted a drive whorl. Antifrictionbearings are provided for supporting the rotor shaft and the exterior ofsuch bearings is rigidly mounted in a sleeve surrounding the rotorshaft. The sleeve is connected with the walls of a bore in the rotorhousing via an elastic member surrounding such sleeve. The sleeve is athinwalled light and rigid metallic sleeve member and the elastic membercomprises a ring of elastomeric material placed upon the end of thethin-walled light metal sleeve facing the turbine. The ring provides anairtight seal for the room or compartment between the sleeve and thebore in the housing at the side of the ring facing away from theturbine. Further there are provided means between the ring sealing thecompartment and the drive whorl for permitting penetration of air intosaid compartment between the sleeve and walls of the bore in the rotorhousing. Such air penetration means may be constituted by a secondelastic outer support member provided for the sleeve at the other end atthe drive side confronting the drive whorl and/or by one or a number ofholes or bores provided at the rotor housing.

13 Claims, 3 Drawing Figures US. Patent Oct. 14, 1975 Sheet10f23,911,659

US. Patent Oct. 14, 1975 Sheet 2 of 2 3,911,659

BEARING ARRANGEMENT FOR A SPINNING ROTOR OF AN OPEN END SPINNING DEVICECROSS-REFERENCE TO RELATED CASE The instant application is acontinuation-in-part of my commonly assigned, copending U.S. applicationSer. No. 383,722, filed July 30, 1973 now abandoned.

BACKGROUND OF THE INVENTION The present invention relates to a new andimproved construction of bearing arrangement for a spinning rotor of anopen end spinning device producing staple fiber yarns in a spinning milloperation.

A spinning rotor for open end spinning (hereinafter sometimes referredto as OE-spinning) arranged in a rotor housing in which sub-atmosphericpressure prevails, is provided at one end with a goblet-shaped fibercollecting surface, hereinafter called a spinning turbine, into whichdiscrete fibers are fed, deposited, and twisted into a yarn, and fromwhich there is then removed a completed yarn. Since the productioncapacity of a machine of this type possessing a multiplicity of suchspinning devices depends directly upon the delivery speed of the yarnand also upon the number of turns per unit of time imparted to the yarn,there are required as high as possible rotational speeds for suchrotors. The rotational speeds which are feasible with present dayspinning technology are in the order of 50,000 to 60,000 rpm.Considering the magnitude of such rotational speeds, it should beself-evident that such high rotational speeds impose very highrequirements upon the bearings. Hence, numerous experiments have beencarried out for the purpose of improving the bearings of open endspinning rotors (hereinafter sometimes referred to as OE-rotors).Attempts have been particularly made to achieve a life of 20,000operating hours for 90% of the bearings at rotational speeds up to45,000 rpm. by using a flexible instead of a rigid bearing arrangement.

Such prior art bearing arrangements consist of two grease lubricatedshoulder ball bearings without an inner race ring. These shoulder ballbearings are arranged at a determined mutual spacing from one anotherwithin a bearing housing surrounded by a double sleeve. One such sleeveis fixed to the bearing housing and the other sleeve is rigidlyconnected to the machine frame. An intermediate layer of an elasticmaterial is arranged between these two sleeves. Since of necessity anair gap is present between the bearing housing and the fixed sleevesurrounding such bearing housing, the latter can carry out radialmovements. The forces acting upon the bearing can be thus reduced, sothat the rotational speed can be increased without impairing the life ofthe bearings. However, relatively large radial deviations are caused inthe state-of-the-art turbine arrangement which can severely impair theprocess of yarn formation.

The prior art arrangement employing bearings which are elasticallysupported by means of an intermediate layer additionally results inlarge radial turbine deviations at critical speeds, complicating theeffective sealing of the open side of the turbine with respect to thehousing and furthermore impairing the process of yarn formation. Sincethe bearing housing including the surrounding sleeve constitutes a verylarge dead mass, there again results undesirably high bearing loads. Afurther disadvantage with the prior art arrangement resides in the factthat through the use of shoulder ball bearings and due to theunavoidable tolerances as concerns the mutual spacing of the bearings aswell as with regard to the spacer sleeve itself, there can occur muchtoo large axial play, causing noise and material fatigue. Anotherdisadvantage exists in terms of the grease lubrication of the ballbearings which is unsuitable at high rotational speeds since dry runningcan occur, causing premature excessive wear of the cage and eventualdestruction of the bearing before the nominal life span of the bearingdetermined by the fatigue limits has been reached.

Continuing, it should be appreciated that hydrostatic air bearings havealready been proposed for OE- spinning rotors. Such type bearingsnecessitate a supply of compressed air for each of the multitude ofspinning rotors arranged on a machine, and this requirement unfavorablyinfluences the price of the machine. Also, the supporting air cushionsare extremely thin, i.e., in the range of thousands of a millimeter, sothat such bearings are quite susceptible to dust particles carried intothe supporting air cushion by the air supply stream, with the resultthat a source of extremely clean air is necessary.

SUMMARY OF THE INVENTION It is a primary object of the present inventionto provide an economically feasible bearing for a spinning rotorpermitting of increased upper limits of the rotational speeds in therange of 50,000 to 60,000 rpm. at quiet running conditions, i.e., smallradial deviations of the spinning turbine, and possessing a sufficientlylow upper critical rotational speed, without detrimentally affecting thelong bearing life span.

A further object of the present invention relates to an improved bearingarrangement for a spinning rotor wherein the bearing units can beexchanged with utmost simplicity, thereby enabling a new bearing to beeasily mounted once the bearing life span has been reached.

Now in order to implement these and still further objects of theinvention, which will become more readily apparent as the descriptionproceeds, and to eliminate the aforementioned drawbacks and limitationsof the prior art proposals, the bearing arrangement for a spinning rotorof an open end spinning device as contemplated by the invention has thespinning rotor incorporating a shaft, at one end of which there ismounted a turbine and at the other end of which there is mounted a drivewhorl. Antifriction bearings are provided for supporting the rotorshaft. The exterior of the bearings is rigidly mounted in a sleeve whichsurrounds the rotor shaft. This sleeve is connected with the walls of abore in the rotor housing via an elastic member which surrounds suchsleeve. Further, the sleeve is a thin-walled light and rigid metallicsleeve member and the elastic member consists of a ring of elastomericmaterial -which is placed upon the end of the thin-walled light metalsleeve confronting the turbine. This ring provides an airtight seal forthe room or compartment between the sleeve and the bore in the housingat the side of the ring facing away from the turbine. Furthermore, thereare provided means for permitting the penetration of air into suchcompartment between the sleeve and the walls of the bore in the rotorhousing. Such air penetration means may be constituted by a secondelastic outer support member provided for the sleeve at the other endthereof at the drive side in the neighborhood of the drive whorl and/orby the provision of one or a number of open-ended bores or holes at therotor housing.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be betterunderstood and objects other than those set forth above, will becomeapparent when consideration is given to the following detaileddescription thereof. Such description makes reference to the annexeddrawings wherein:

FIG. 1 is a longitudinal sectional view of a bearing arrangement of aspinning rotor designed according to the teachings of the presentinvention;

FIG. 2 is a cross-sectional view taken substantially along the lineIl-ll of FIG. 1;

FIG. 3 is a longitudinal sectional view, similar to the showing of FIG.1, of a modified construction of bearing arrangement of a spinningrotor.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Describing now thedrawings, in the various embodiments disclosed herein, and particularlyreferring for instance to FIGS. 1 and 2, a rotor housing 1 is sealed bya cover 2 containing a fiber supply duct 3 by means of which discretefibers 4 are transported under the action of an air stream to a fibercollecting surface 5 of a so-called turbine 6 of a rotatable rotor 7.The pressure drop required for transporting the fibers 4 is generated byconnecting the rotor housing 1 with a suitable and therefore notparticularly illustrated vacuum source through the agency of a duct orconduit 8. Of course, the pressure drop could also be generated by therotor itself, e.g., by means of radial holes or fan blades provided onthe turbine.

The rotor 7 consists of a rotor shaft 9 rotatably supported at the sidethereof facing the turbine 6 by a grooved ball bearing 10 determiningthe axial position. At the other end of the rotor 7 and specifically therotor shaft 9, there is mounted a drive whorl 11 about which there canbe trained a drive belt 12. At the drive side of the arrangement thereis mounted a roller bearing 13 which provides a higher static anddynamic load capacity in radial direction, so that the forcestransmitted by the drive belt 12 can be easily absorbed. The outer ringsor races 13' and 13" of both brearings l0 and 13 are rigidly mounted ina lightweight and rigid aluminum sleeve 14 of small wall thickness.

The thin-walled sleeve 14 itself is supported in a bore 16 of thehousing 1 at the region of the grooved ball bearing 10 by means of arelatively small and thin rubber ring 15. This ring 15, formed ofelastomeric material, also seals the air so as to suppress the flow ofair from the room or compartment 17' between the sleeve 14 and the bore16 of the housing into the room or compartment 17 surrounding theturbine 6 where there prevails subatmospheric pressure, so that there isnot disturbed the air throughput balance of the turbine 6. For the samepurpose, the sleeve 14 externally of the grooved ball bearing 10 isprovided with a cover member or cover 18 with respect to the room orcompartment 17, a small clearance 19 of course being maintained withrespect to the rotor shaft 9. By means of this clearance gap 19 thesub-atmospheric pressure which prevails in the room 17 generates arelatively small air current, which is sucked in through holes orapertures 20 in the sleeve 14 from the room or compartment 17 betweenthe sleeve 14 and the bore 16 of the housing 1 while bypassing thebearing. Hence, the pressure on both sides of the grooved ball bearing10 is thus equalized. By the same token, migration oflubricant from thegrooved ball bearing 10 towards the turbine 6 is effectively prevented.This is of particular importance in the case of oil lubricated ballbearings, which at the present time are the only type of antifrictionbearings permitting the highest rotational speeds. The rubber orelastomeric ring 15 thus fulfills several important functions in that itmaintains the deviation of the rotor within close limits as an elasticmember which is placed in the vicinity of the turbine andnotwithstanding its softness, and also is used as a means forpractically equalizing the pressure at both sides of the grooved ballbearing 10.

Furthermore, the generated airstream flowing through the clearance gap19, before passing through the holes 20, flows along the rubber ring 15and the outside of the sleeve 14, cooling both of these components. Atthe drive side, that is at the side of the sleeve which confronts thedrive whorl 11, the sleeve 14 is supported in the bore 16 of the housingby a number of rubber blocks 21 or equivalent elastic support means, andthese rubber blocks 21 are uniformly distributed along the circumferenceof the aforesaid end of the sleeve 14, so that cooling air can penetratebetween the sleeve 14 and the bore 16 of the housing 1. The use of aroller bearing 13 at this location exhibits the advantage that the axialplay is not determined by this bearing 13, but by the grooved ballbearing 10, and that the unavoidable length tolerances of the bearings,the shaft and of the sleeve 14, cannot influence the axial play of thebearing. Furthermore, the roller bearing 13 has a longer life span anddevelops less bearing noise if only loaded in radial direction. Due tothe cooperation of the two elastic elements, i.e., the ring 15 and therubber blocks 21 which are mutually spaced as far as possible from oneanother, it is possible to maintain as small as possible the turbinedeviations at the normal operating speeds as well as duringpredetermined critical speeds and caused by uneven running of the drivebelts. This is of great importance for the undisturbed yarn formationprocess. Since the dead mass, i.e., all elastically supported butnon-rotating elements, is kept to a minimum, the bearing load caused byvibrations is reduced and the fatigue limit of the two bearings 10 and13 is extended, so that the bearing life span is prolonged. The criticalrotational speeds, however, in this arrangement are increased. Bysuitably varying the characteristics of the elastic members it ispossible to carry out adaptation of the critical speeds to practicalrequirements within certain limits. This adaptation, however, isinsufficient for requirements occurring with OE spinning devices, e.g.in case the bobbin change is to be effected at a low speed. In suchcases the increase of the mass of the turbine 6, as indicated in FIG. 1with dash-dotted lines, by an additional weight 22' is recommended. Inthis manner the lower limit of the range of hypercritical rotationalspeeds is considerably lowered. The bearing arrangement hereindisclosed, and using grease lubrication, can be operated at rotationalspeeds of up to 45,000 rpm. with a practically acceptable life span. Oillubrication, which is the only lubrication technique which as apractical matter permits the highest possible rotational speeds, iseffected in the following manner:

A nozzle or mouthpiece 23 threadably connected with the housing 1 isconnected with a hose 22 which guides a wick 25 extending down into areservoir 24. An extension 26 of the nozzle 23 penetrates through anopening 27 in the sleeve 14 and the wick 25 releases the oil drop bydrop, that is to say, with a metered flow, to the rotating shaft 9, fromwhich location the oil flows to the two bearings and 13. A disk 28,which throws off the oil, prevents the penetration of oil into theturbine room or compartment 17.

In the wick lubrication arrangement the supply quantity of oil isdetermined by the cross-sectional area of the wick 25 and theelevational difference between the reservoir 24 and the bearings 10 and13. The supply quantity of oil can be metered such that it correspondsto the effective requirements. The oil which continues to drip during astandstill period of the machine, however, can overfill the bearings.Thus, suitable precautions must be undertaken to assure that excess oilis thrown out of the bearings as the machine is started up. A furtherpossible variation of oil lubrication system resides in the use of aconventional central lubrication system by means of which, atpredetermined timeintervals, a controlled pressure is applied to thesupply line by a supply pump supplying the oil to a metering piston, sothat the oil quantity drips in selectable steps or stages into thebearing arrangement.

Finally, in FIG. 3 there is disclosed a modified construction of bearingarrangement for a spinning rotor, similar to the showing of FIG. 1, andwherein generally the same reference characters have been employed forthe same components. This modified construction of bearing arrangementdiffers from that shown in FIGS. 1 and 2 in that here there is providedone or a number of air admission holes or bores 30 extending radiallythrough the rotor housing 1 from the outside wall thereof to the innerwall thereof, each such hole or bore 30 being located between the ringand the drive whorl 11. In this case, the rubber blocks 21 at the sideof the drive whorl 11 may either extend continuously about theassociated end of the sleeve 14 or may be constructed and arranged inthe manner previously disclosed with respect to the embodiment of FIGS.1 and 2, and as best seen by referring to FIG. 2. Each such bore 30 isconveniently covered by a suitable filter 31 so as to filter theincoming air. The bore or bores 30 permit the penetration of air intothe room or compartment 17'.

While there is shown and described present preferred embodiments of theinvention, it is to be distinctly understood that the invention is notlimited thereto, but may be otherwise variously embodied and practicedwithin the scope of the following claims. Accordingly,

What is claimed is:

1. A bearing arrangement for a spinning rotor of an open end spinningdevice, comprising a rotor housing, a spinning rotor incorporating ashaft having opposed ends, said shaft being arranged in said rotorhousing, a turbine mounted at one end of the shaft, a drive whorlmounted at the other end of said shaft, antifriction bearings forsupporting said shaft, a sleeve surrounding said shaft for rigidlymounting the antifriction bearings thereat, said rotor housing have abore bonded by a wall, an elastic member surrounding said sleeve andconnecting said sleeve with the wall of said bore, said sleeve beingconstituted by a thin-walled light and rigid metallic sleeve, saidelastic member comprising a ring of elastomeric material placed upon theend of the thinwalled light metallic sleeve confronting the turbine,said sleeve being spaced from the wall of said bore to define acompartment therebetween, said ring sealing said compartment betweensaid sleeve and the wall of said bore in the housing, and means providedbetween said ring which seals said compartment and said drive whorl forpermitting the penetration of air into said compartment.

2. The bearing arrangement as defined in claim 1, wherein said airpenetration means comprises a second elastic outer support memberprovided for said sleeve at an end thereof defining a drive side whichconfronts the drive whorl, said second elastic outer support memberpermitting the penetration of air into said compartment between thesleeve and the wall of the bore in the rotor housing.

3. The bearing arrangement as defined in claim 1, wherein said airpenetration means comprise at least one bore provided for said rotorhousing for permitting the penetration of air into said compartmentbetween the sleeve and the wall of the bore in the rotor housing.

4. The bearing arrangement as defined in claim 1, wherein the exteriorof said antifriction bearings are rigidly mounted at said sleeve.

5. The bearing arrangement as defined in claim I, wherein one of saidantifriction bearings comprises a grooved ball bearing and another ofsaid antifriction bearings comprises an axially non-guiding antifrictionbearing, said grooved ball bearing being located at the end of the shaftconfronting the turbine for rotatably supporting and axially guidingsaid shaft, the other end of said shaft constituting the drive side ofsaid shaft, said drive side of said shaft being rotatably supported bysaid axially nonguiding antifriction bearing.

6. The bearing arrangement as defined in claim 5, wherein said axiallynon-guiding antifriction bearing is a roller bearing.

7. The bearing arrangement as defined in claim 5, wherein said ring ofelastomeric material, viewed in axial direction, is arranged externallyof the grooved ball bearing, said sleeve having air throughpassageopenings located between the grooved ball bearing and the ring ofelastomeric material.

8. The bearing arrangement as defined in claim 7, further including aclosure provided for the sleeve at the side confronting the turbine,said closure providing a clearance with respect to the rotor shaft, andwherein in the space between the closure and the grooved ball bearingthere prevails approximately atmospheric pressure.

9. The bearing arrangement as defined in claim 1, further including anoil drop metering device provided between said antifriction bearings forsupplying oil in drops to the rotor shaft.

10. The bearing arrangement as defined in claim 1, further including anadditional weight for increasing the mass of said turbine.

11. The bearing arrangement as defined in claim 1, wherein said sleeveis formed of a light metal.

12. The bearing arrangement as defined in claim 11, wherein the lightmetal of the sleeve is aluminum.

13. The bearing arrangement as defined in claim 1, further including asecond elastic outer support member provided for said sleeve at an endthereof defining a drive side which confronts the drive whorl.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3,911,59 DATED October 14, 19 75 INVENTOR(S) IGERHARD MANDL It is certifiedthat error appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

In the Heading, left-hand column, after item [21] insert the followingnew line:

[30] Foreign Application Priority Data August 17, 1972 Switzerland12l84/72- Column 5, line 63 "bonded" should read --bounded.

Signed and Sealed this second Day Of March 1976 [SEAL] A ttes t:

1. A bearing arrangement for a spinning rotor of an open end spinningdevice, comprising a rotor housing, a spinning rotor incorporating ashaft having opposed ends, said shaft being arranged in said rotorhousing, a turbine mounted at one end of the shaft, a drive whorlmounted at the other end of said shaft, antifriction bearings forsupporting said shaft, a sleeve surrounding said shaft for rigidlymounting the antifriction bearings thereat, said rotor housing have abore bonded by a wall, an elastic member surrounding said sleeve andconnecting said sleeve with the wall of said bore, said sleeve beingconstituted by a thin-walled light and rigid metallic sleeve, saidelastic member comprising a ring of elastomeric material placed upon theend of the thin-walled light metallic sleeve confronting the turbine,said sleeve being spaced from the wall of said bore to define acompartment therebetween, said ring sealing said compartment betweensaid sleeve and the wall of said bore in the housing, and means providedbetween said ring which seals said compartment and said drive whorl forpermitting the penetration of air into said compartment.
 2. The bearingarrangement as defined in claim 1, wherein said air penetration meanscomprises a second elastic outer support member provided for said sleeveat an end thEreof defining a drive side which confronts the drive whorl,said second elastic outer support member permitting the penetration ofair into said compartment between the sleeve and the wall of the bore inthe rotor housing.
 3. The bearing arrangement as defined in claim 1,wherein said air penetration means comprise at least one bore providedfor said rotor housing for permitting the penetration of air into saidcompartment between the sleeve and the wall of the bore in the rotorhousing.
 4. The bearing arrangement as defined in claim 1, wherein theexterior of said antifriction bearings are rigidly mounted at saidsleeve.
 5. The bearing arrangement as defined in claim 1, wherein one ofsaid antifriction bearings comprises a grooved ball bearing and anotherof said antifriction bearings comprises an axially non-guidingantifriction bearing, said grooved ball bearing being located at the endof the shaft confronting the turbine for rotatably supporting andaxially guiding said shaft, the other end of said shaft constituting thedrive side of said shaft, said drive side of said shaft being rotatablysupported by said axially nonguiding antifriction bearing.
 6. Thebearing arrangement as defined in claim 5, wherein said axiallynon-guiding antifriction bearing is a roller bearing.
 7. The bearingarrangement as defined in claim 5, wherein said ring of elastomericmaterial, viewed in axial direction, is arranged externally of thegrooved ball bearing, said sleeve having air throughpassage openingslocated between the grooved ball bearing and the ring of elastomericmaterial.
 8. The bearing arrangement as defined in claim 7, furtherincluding a closure provided for the sleeve at the side confronting theturbine, said closure providing a clearance with respect to the rotorshaft, and wherein in the space between the closure and the grooved ballbearing there prevails approximately atmospheric pressure.
 9. Thebearing arrangement as defined in claim 1, further including an oil dropmetering device provided between said antifriction bearings forsupplying oil in drops to the rotor shaft.
 10. The bearing arrangementas defined in claim 1, further including an additional weight forincreasing the mass of said turbine.
 11. The bearing arrangement asdefined in claim 1, wherein said sleeve is formed of a light metal. 12.The bearing arrangement as defined in claim 11, wherein the light metalof the sleeve is aluminum.
 13. The bearing arrangement as defined inclaim 1, further including a second elastic outer support memberprovided for said sleeve at an end thereof defining a drive side whichconfronts the drive whorl.